Lord Du Mesnil is to undergo tests after suffering from post-race heat stress following the Welsh National.

Trainer Richard Hobson is determined to discover the root of the problem before making any future plans for his smart long-distance chaser.

Lord Du Mesnil first had an issue when he was runner-up in the National Hunt Chase at Cheltenham in March, and again overheated after he finished ninth at Chepstow on Saturday.

“It was obviously a bit disappointing to see him do that again, but we’re going to take some tests this week to see if there’s something lacking,” said Hobson.

“He shouldn’t have run, though. I walked the course, and it was disappointing for me to have him in good order and run him on ground that didn’t suit.

“He wants it like a bog. He wants proper soft conditions, and he didn’t get it. The covers clearly did a good job.”

A return to soft or heavy ground will therefore be prescribed, but not before Hobson has thoroughly investigated the reasons for his heat stress.

“When this horse started winning races, that was his asset,” added the Cotswolds trainer.

“He was able to gallop through deep ground at Newcastle, at Haydock and when he was second at Cheltenham, when other horses couldn’t.

“I want to do a few tests on him. I want to make sure I understand a little bit more why he’s overheating, so we need to get that sorted.”

Hobson has another exciting prospect in De Forgotten One, who won a qualifier for the Northern Lights Middle Distance Chase Series at Catterick.

The seven-year-old had previously run third to Some Neck over Cheltenham’s cross-country course.

“He’s gone up 10lb, and the Topham is his long-term aim,” said Hobson.

“He’s had four runs for us, the first two in France. He’s young, he’s very exciting, very professional and as good a jumper as you’ll see. He has a big future.”